/**
 * Intro.js v1.1.0
 * https://github.com/usablica/intro.js
 * MIT licensed
 *
 * Copyright (C) 2013 usabli.ca - A weekend project by Afshin Mehrabani (@afshinmeh)
 */

(function (root, factory) {
    if (typeof exports === 'object') {
        // CommonJS
        factory(exports);
    } else if (typeof define === 'function' && define.amd) {
        // AMD. Register as an anonymous module.
        define(['exports'], factory);
    } else {
        // Browser globals
        factory(root);
    }
} (this, function (exports) {
    //Default config/variables
    var VERSION = '1.1.0';

    /**
     * IntroJs main class
     *
     * @class IntroJs
     */
    function IntroJs(obj) {
        this._targetElement = obj;

        this._options = {
            /* Next button label in tooltip box */
            nextLabel: 'Next &rarr;',
            /* Previous button label in tooltip box */
            prevLabel: '&larr; Back',
            /* Skip button label in tooltip box */
            skipLabel: 'Skip',
            /* Done button label in tooltip box */
            doneLabel: 'Done',
            /* Default tooltip box position */
            tooltipPosition: 'bottom',
            /* Next CSS class for tooltip boxes */
            tooltipClass: '',
            /* CSS class that is added to the helperLayer */
            highlightClass: '',
            /* Close introduction when pressing Escape button? */
            exitOnEsc: true,
            /* Close introduction when clicking on overlay layer? */
            exitOnOverlayClick: true,
            /* Show step numbers in introduction? */
            showStepNumbers: true,
            /* Let user use keyboard to navigate the tour? */
            keyboardNavigation: true,
            /* Show tour control buttons? */
            showButtons: true,
            /* Show tour bullets? */
            showBullets: true,
            /* Show tour progress? */
            showProgress: false,
            /* Scroll to highlighted element? */
            scrollToElement: true,
            /* Set the overlay opacity */
            overlayOpacity: 0.8,
            /* Precedence of positions, when auto is enabled */
            positionPrecedence: ["bottom", "top", "right", "left"],
            /* Disable an interaction with element? */
            disableInteraction: false
        };
    }

    /**
     * Initiate a new introduction/guide from an element in the page
     *
     * @api private
     * @method _introForElement
     * @param {Object} targetElm
     * @returns {Boolean} Success or not?
     */
    function _introForElement(targetElm) {
        var introItems = [],
            self = this;

        if (this._options.steps) {
            //use steps passed programmatically
            for (var i = 0, stepsLength = this._options.steps.length; i < stepsLength; i++) {
                var currentItem = _cloneObject(this._options.steps[i]);
                //set the step
                currentItem.step = introItems.length + 1;
                //use querySelector function only when developer used CSS selector
                if (typeof(currentItem.element) === 'string') {
                    //grab the element with given selector from the page
                    currentItem.element = document.querySelector(currentItem.element);
                }

                //intro without element
                if (typeof(currentItem.element) === 'undefined' || currentItem.element == null) {
                    var floatingElementQuery = document.querySelector(".introjsFloatingElement");

                    if (floatingElementQuery == null) {
                        floatingElementQuery = document.createElement('div');
                        floatingElementQuery.className = 'introjsFloatingElement';

                        document.body.appendChild(floatingElementQuery);
                    }

                    currentItem.element  = floatingElementQuery;
                    currentItem.position = 'floating';
                }

                if (currentItem.element != null) {
                    introItems.push(currentItem);
                }
            }

        } else {
            //use steps from data-* annotations
            var allIntroSteps = targetElm.querySelectorAll('*[data-intro]');
            //if there's no element to intro
            if (allIntroSteps.length < 1) {
                return false;
            }

            //first add intro items with data-step
            for (var i = 0, elmsLength = allIntroSteps.length; i < elmsLength; i++) {
                var currentElement = allIntroSteps[i];
                var step = parseInt(currentElement.getAttribute('data-step'), 10);

                if (step > 0) {
                    introItems[step - 1] = {
                        element: currentElement,
                        intro: currentElement.getAttribute('data-intro'),
                        step: parseInt(currentElement.getAttribute('data-step'), 10),
                        tooltipClass: currentElement.getAttribute('data-tooltipClass'),
                        highlightClass: currentElement.getAttribute('data-highlightClass'),
                        position: currentElement.getAttribute('data-position') || this._options.tooltipPosition
                    };
                }
            }

            //next add intro items without data-step
            //todo: we need a cleanup here, two loops are redundant
            var nextStep = 0;
            for (var i = 0, elmsLength = allIntroSteps.length; i < elmsLength; i++) {
                var currentElement = allIntroSteps[i];

                if (currentElement.getAttribute('data-step') == null) {

                    while (true) {
                        if (typeof introItems[nextStep] == 'undefined') {
                            break;
                        } else {
                            nextStep++;
                        }
                    }

                    introItems[nextStep] = {
                        element: currentElement,
                        intro: currentElement.getAttribute('data-intro'),
                        step: nextStep + 1,
                        tooltipClass: currentElement.getAttribute('data-tooltipClass'),
                        highlightClass: currentElement.getAttribute('data-highlightClass'),
                        position: currentElement.getAttribute('data-position') || this._options.tooltipPosition
                    };
                }
            }
        }

        //removing undefined/null elements
        var tempIntroItems = [];
        for (var z = 0; z < introItems.length; z++) {
            introItems[z] && tempIntroItems.push(introItems[z]);  // copy non-empty values to the end of the array
        }

        introItems = tempIntroItems;

        //Ok, sort all items with given steps
        introItems.sort(function (a, b) {
            return a.step - b.step;
        });

        //set it to the introJs object
        self._introItems = introItems;

        //add overlay layer to the page
        if(_addOverlayLayer.call(self, targetElm)) {
            //then, start the show
            _nextStep.call(self);

            var skipButton     = targetElm.querySelector('.introjs-skipbutton'),
                nextStepButton = targetElm.querySelector('.introjs-nextbutton');

            self._onKeyDown = function(e) {
                if (e.keyCode === 27 && self._options.exitOnEsc == true) {
                    //escape key pressed, exit the intro
                    //check if exit callback is defined
                    if (self._introExitCallback != undefined) {
                        self._introExitCallback.call(self);
                    }
                    _exitIntro.call(self, targetElm);
                } else if(e.keyCode === 37) {
                    //left arrow
                    _previousStep.call(self);
                } else if (e.keyCode === 39) {
                    //right arrow
                    _nextStep.call(self);
                } else if (e.keyCode === 13) {
                    //srcElement === ie
                    var target = e.target || e.srcElement;
                    if (target && target.className.indexOf('introjs-prevbutton') > 0) {
                        //user hit enter while focusing on previous button
                        _previousStep.call(self);
                    } else if (target && target.className.indexOf('introjs-skipbutton') > 0) {
                        //user hit enter while focusing on skip button
                        if (self._introItems.length - 1 == self._currentStep && typeof (self._introCompleteCallback) === 'function') {
                            self._introCompleteCallback.call(self);
                        }
                        //check if any callback is defined
                        if (self._introExitCallback != undefined) {
                            self._introExitCallback.call(self);
                        }
                        _exitIntro.call(self, targetElm);
                    } else {
                        //default behavior for responding to enter
                        _nextStep.call(self);
                    }

                    //prevent default behaviour on hitting Enter, to prevent steps being skipped in some browsers
                    if(e.preventDefault) {
                        e.preventDefault();
                    } else {
                        e.returnValue = false;
                    }
                }
            };

            self._onResize = function(e) {
                _setHelperLayerPosition.call(self, document.querySelector('.introjs-helperLayer'));
                _setHelperLayerPosition.call(self, document.querySelector('.introjs-tooltipReferenceLayer'));
            };

            if (window.addEventListener) {
                if (this._options.keyboardNavigation) {
                    window.addEventListener('keydown', self._onKeyDown, true);
                }
                //for window resize
                window.addEventListener('resize', self._onResize, true);
            } else if (document.attachEvent) { //IE
                if (this._options.keyboardNavigation) {
                    document.attachEvent('onkeydown', self._onKeyDown);
                }
                //for window resize
                document.attachEvent('onresize', self._onResize);
            }
        }
        return false;
    }

    /*
     * makes a copy of the object
     * @api private
     * @method _cloneObject
     */
    function _cloneObject(object) {
        if (object == null || typeof (object) != 'object' || typeof (object.nodeType) != 'undefined') {
            return object;
        }
        var temp = {};
        for (var key in object) {
            if (typeof (jQuery) != 'undefined' && object[key] instanceof jQuery) {
                temp[key] = object[key];
            } else {
                temp[key] = _cloneObject(object[key]);
            }
        }
        return temp;
    }
    /**
     * Go to specific step of introduction
     *
     * @api private
     * @method _goToStep
     */
    function _goToStep(step) {
        //because steps starts with zero
        this._currentStep = step - 2;
        if (typeof (this._introItems) !== 'undefined') {
            _nextStep.call(this);
        }
    }

    /**
     * Go to next step on intro
     *
     * @api private
     * @method _nextStep
     */
    function _nextStep() {
        this._direction = 'forward';

        if (typeof (this._currentStep) === 'undefined') {
            this._currentStep = 0;
        } else {
            ++this._currentStep;
        }

        if ((this._introItems.length) <= this._currentStep) {
            //end of the intro
            //check if any callback is defined
            if (typeof (this._introCompleteCallback) === 'function') {
                this._introCompleteCallback.call(this);
            }
            _exitIntro.call(this, this._targetElement);
            return;
        }

        var nextStep = this._introItems[this._currentStep];
        if (typeof (this._introBeforeChangeCallback) !== 'undefined') {
            this._introBeforeChangeCallback.call(this, nextStep.element);
        }

        _showElement.call(this, nextStep);
    }

    /**
     * Go to previous step on intro
     *
     * @api private
     * @method _nextStep
     */
    function _previousStep() {
        this._direction = 'backward';

        if (this._currentStep === 0) {
            return false;
        }

        var nextStep = this._introItems[--this._currentStep];
        if (typeof (this._introBeforeChangeCallback) !== 'undefined') {
            this._introBeforeChangeCallback.call(this, nextStep.element);
        }

        _showElement.call(this, nextStep);
    }

    /**
     * Exit from intro
     *
     * @api private
     * @method _exitIntro
     * @param {Object} targetElement
     */
    function _exitIntro(targetElement) {
        //remove overlay layer from the page
        var overlayLayer = targetElement.querySelector('.introjs-overlay');

        //return if intro already completed or skipped
        if (overlayLayer == null) {
            return;
        }

        //for fade-out animation
        overlayLayer.style.opacity = 0;
        setTimeout(function () {
            if (overlayLayer.parentNode) {
                overlayLayer.parentNode.removeChild(overlayLayer);
            }
        }, 500);

        //remove all helper layers
        var helperLayer = targetElement.querySelector('.introjs-helperLayer');
        if (helperLayer) {
            helperLayer.parentNode.removeChild(helperLayer);
        }

        var referenceLayer = targetElement.querySelector('.introjs-tooltipReferenceLayer');
        if (referenceLayer) {
            referenceLayer.parentNode.removeChild(referenceLayer);
        }
        //remove disableInteractionLayer
        var disableInteractionLayer = targetElement.querySelector('.introjs-disableInteraction');
        if (disableInteractionLayer) {
            disableInteractionLayer.parentNode.removeChild(disableInteractionLayer);
        }

        //remove intro floating element
        var floatingElement = document.querySelector('.introjsFloatingElement');
        if (floatingElement) {
            floatingElement.parentNode.removeChild(floatingElement);
        }

        //remove `introjs-showElement` class from the element
        var showElement = document.querySelector('.introjs-showElement');
        if (showElement) {
            showElement.className = showElement.className.replace(/introjs-[a-zA-Z]+/g, '').replace(/^\s+|\s+$/g, ''); // This is a manual trim.
        }

        //remove `introjs-fixParent` class from the elements
        var fixParents = document.querySelectorAll('.introjs-fixParent');
        if (fixParents && fixParents.length > 0) {
            for (var i = fixParents.length - 1; i >= 0; i--) {
                fixParents[i].className = fixParents[i].className.replace(/introjs-fixParent/g, '').replace(/^\s+|\s+$/g, '');
            }
        }

        //clean listeners
        if (window.removeEventListener) {
            window.removeEventListener('keydown', this._onKeyDown, true);
        } else if (document.detachEvent) { //IE
            document.detachEvent('onkeydown', this._onKeyDown);
        }

        //set the step to zero
        this._currentStep = undefined;
    }

    /**
     * Render tooltip box in the page
     *
     * @api private
     * @method _placeTooltip
     * @param {HTMLElement} targetElement
     * @param {HTMLElement} tooltipLayer
     * @param {HTMLElement} arrowLayer
     * @param {HTMLElement} helperNumberLayer
     */
    function _placeTooltip(targetElement, tooltipLayer, arrowLayer, helperNumberLayer) {
        var tooltipCssClass = '',
            currentStepObj,
            tooltipOffset,
            targetOffset,
            windowSize,
            currentTooltipPosition;

        //reset the old style
        tooltipLayer.style.top        = null;
        tooltipLayer.style.right      = null;
        tooltipLayer.style.bottom     = null;
        tooltipLayer.style.left       = null;
        tooltipLayer.style.marginLeft = null;
        tooltipLayer.style.marginTop  = null;

        arrowLayer.style.display = 'inherit';

        if (typeof(helperNumberLayer) != 'undefined' && helperNumberLayer != null) {
            helperNumberLayer.style.top  = null;
            helperNumberLayer.style.left = null;
        }

        //prevent error when `this._currentStep` is undefined
        if (!this._introItems[this._currentStep]) return;

        //if we have a custom css class for each step
        currentStepObj = this._introItems[this._currentStep];
        if (typeof (currentStepObj.tooltipClass) === 'string') {
            tooltipCssClass = currentStepObj.tooltipClass;
        } else {
            tooltipCssClass = this._options.tooltipClass;
        }

        tooltipLayer.className = ('introjs-tooltip ' + tooltipCssClass).replace(/^\s+|\s+$/g, '');

        currentTooltipPosition = this._introItems[this._currentStep].position;
        if ((currentTooltipPosition == "auto" || this._options.tooltipPosition == "auto")) {
            if (currentTooltipPosition != "floating") { // Floating is always valid, no point in calculating
                currentTooltipPosition = _determineAutoPosition.call(this, targetElement, tooltipLayer, currentTooltipPosition);
            }
        }
        targetOffset  = _getOffset(targetElement);
        tooltipOffset = _getOffset(tooltipLayer);
        windowSize    = _getWinSize();
        switch (currentTooltipPosition) {
            case 'top':
                arrowLayer.className = 'introjs-arrow bottom';

                var tooltipLayerStyleLeft = 15;
                _checkRight(targetOffset, tooltipLayerStyleLeft, tooltipOffset, windowSize, tooltipLayer);
                tooltipLayer.style.bottom = (targetOffset.height +  20) + 'px';
                break;
            case 'right':
                tooltipLayer.style.left = (targetOffset.width + 20) + 'px';
                if (targetOffset.top + tooltipOffset.height > windowSize.height) {
                    // In this case, right would have fallen below the bottom of the screen.
                    // Modify so that the bottom of the tooltip connects with the target
                    arrowLayer.className = "introjs-arrow left-bottom";
                    tooltipLayer.style.top = "-" + (tooltipOffset.height - targetOffset.height - 20) + "px";
                } else {
                    arrowLayer.className = 'introjs-arrow left';
                }
                break;
            case 'left':
                if (this._options.showStepNumbers == true) {
                    tooltipLayer.style.top = '15px';
                }

                if (targetOffset.top + tooltipOffset.height > windowSize.height) {
                    // In this case, left would have fallen below the bottom of the screen.
                    // Modify so that the bottom of the tooltip connects with the target
                    tooltipLayer.style.top = "-" + (tooltipOffset.height - targetOffset.height - 20) + "px";
                    arrowLayer.className = 'introjs-arrow right-bottom';
                } else {
                    arrowLayer.className = 'introjs-arrow right';
                }
                tooltipLayer.style.right = (targetOffset.width + 20) + 'px';

                break;
            case 'floating':
                arrowLayer.style.display = 'none';

                //we have to adjust the top and left of layer manually for intro items without element
                tooltipLayer.style.left   = '50%';
                tooltipLayer.style.top    = '50%';
                tooltipLayer.style.marginLeft = '-' + (tooltipOffset.width / 2)  + 'px';
                tooltipLayer.style.marginTop  = '-' + (tooltipOffset.height / 2) + 'px';

                if (typeof(helperNumberLayer) != 'undefined' && helperNumberLayer != null) {
                    helperNumberLayer.style.left = '-' + ((tooltipOffset.width / 2) + 18) + 'px';
                    helperNumberLayer.style.top  = '-' + ((tooltipOffset.height / 2) + 18) + 'px';
                }

                break;
            case 'bottom-right-aligned':
                arrowLayer.className      = 'introjs-arrow top-right';

                var tooltipLayerStyleRight = 0;
                _checkLeft(targetOffset, tooltipLayerStyleRight, tooltipOffset, tooltipLayer);
                tooltipLayer.style.top    = (targetOffset.height +  20) + 'px';
                break;

            case 'bottom-middle-aligned':
                arrowLayer.className      = 'introjs-arrow top-middle';

                var tooltipLayerStyleLeftRight = targetOffset.width / 2 - tooltipOffset.width / 2;
                if (_checkLeft(targetOffset, tooltipLayerStyleLeftRight, tooltipOffset, tooltipLayer)) {
                    tooltipLayer.style.right = null;
                    _checkRight(targetOffset, tooltipLayerStyleLeftRight, tooltipOffset, windowSize, tooltipLayer);
                }
                tooltipLayer.style.top = (targetOffset.height + 20) + 'px';
                break;

            case 'bottom-left-aligned':
            // Bottom-left-aligned is the same as the default bottom
            case 'bottom':
            // Bottom going to follow the default behavior
            default:
                arrowLayer.className = 'introjs-arrow top';

                var tooltipLayerStyleLeft = 0;
                _checkRight(targetOffset, tooltipLayerStyleLeft, tooltipOffset, windowSize, tooltipLayer);
                tooltipLayer.style.top    = (targetOffset.height +  20) + 'px';
                break;
        }
    }

    /**
     * Set tooltip left so it doesn't go off the right side of the window
     *
     * @return boolean true, if tooltipLayerStyleLeft is ok.  false, otherwise.
     */
    function _checkRight(targetOffset, tooltipLayerStyleLeft, tooltipOffset, windowSize, tooltipLayer) {
        if (targetOffset.left + tooltipLayerStyleLeft + tooltipOffset.width > windowSize.width) {
            // off the right side of the window
            tooltipLayer.style.left = (windowSize.width - tooltipOffset.width - targetOffset.left) + 'px';
            return false;
        }
        tooltipLayer.style.left = tooltipLayerStyleLeft + 'px';
        return true;
    }

    /**
     * Set tooltip right so it doesn't go off the left side of the window
     *
     * @return boolean true, if tooltipLayerStyleRight is ok.  false, otherwise.
     */
    function _checkLeft(targetOffset, tooltipLayerStyleRight, tooltipOffset, tooltipLayer) {
        if (targetOffset.left + targetOffset.width - tooltipLayerStyleRight - tooltipOffset.width < 0) {
            // off the left side of the window
            tooltipLayer.style.left = (-targetOffset.left) + 'px';
            return false;
        }
        tooltipLayer.style.right = tooltipLayerStyleRight + 'px';
        return true;
    }

    /**
     * Determines the position of the tooltip based on the position precedence and availability
     * of screen space.
     *
     * @param {Object} targetElement
     * @param {Object} tooltipLayer
     * @param {Object} desiredTooltipPosition
     *
     */
    function _determineAutoPosition(targetElement, tooltipLayer, desiredTooltipPosition) {

        // Take a clone of position precedence. These will be the available
        var possiblePositions = this._options.positionPrecedence.slice();

        var windowSize = _getWinSize();
        var tooltipHeight = _getOffset(tooltipLayer).height + 10;
        var tooltipWidth = _getOffset(tooltipLayer).width + 20;
        var targetOffset = _getOffset(targetElement);

        // If we check all the possible areas, and there are no valid places for the tooltip, the element
        // must take up most of the screen real estate. Show the tooltip floating in the middle of the screen.
        var calculatedPosition = "floating";

        // Check if the width of the tooltip + the starting point would spill off the right side of the screen
        // If no, neither bottom or top are valid
        if (targetOffset.left + tooltipWidth > windowSize.width || ((targetOffset.left + (targetOffset.width / 2)) - tooltipWidth) < 0) {
            _removeEntry(possiblePositions, "bottom");
            _removeEntry(possiblePositions, "top");
        } else {
            // Check for space below
            if ((targetOffset.height + targetOffset.top + tooltipHeight) > windowSize.height) {
                _removeEntry(possiblePositions, "bottom");
            }

            // Check for space above
            if (targetOffset.top - tooltipHeight < 0) {
                _removeEntry(possiblePositions, "top");
            }
        }

        // Check for space to the right
        if (targetOffset.width + targetOffset.left + tooltipWidth > windowSize.width) {
            _removeEntry(possiblePositions, "right");
        }

        // Check for space to the left
        if (targetOffset.left - tooltipWidth < 0) {
            _removeEntry(possiblePositions, "left");
        }

        // At this point, our array only has positions that are valid. Pick the first one, as it remains in order
        if (possiblePositions.length > 0) {
            calculatedPosition = possiblePositions[0];
        }

        // If the requested position is in the list, replace our calculated choice with that
        if (desiredTooltipPosition && desiredTooltipPosition != "auto") {
            if (possiblePositions.indexOf(desiredTooltipPosition) > -1) {
                calculatedPosition = desiredTooltipPosition;
            }
        }

        return calculatedPosition;
    }

    /**
     * Remove an entry from a string array if it's there, does nothing if it isn't there.
     *
     * @param {Array} stringArray
     * @param {String} stringToRemove
     */
    function _removeEntry(stringArray, stringToRemove) {
        if (stringArray.indexOf(stringToRemove) > -1) {
            stringArray.splice(stringArray.indexOf(stringToRemove), 1);
        }
    }

    /**
     * Update the position of the helper layer on the screen
     *
     * @api private
     * @method _setHelperLayerPosition
     * @param {Object} helperLayer
     */
    function _setHelperLayerPosition(helperLayer) {
        if (helperLayer) {
            //prevent error when `this._currentStep` in undefined
            if (!this._introItems[this._currentStep]) return;

            var currentElement  = this._introItems[this._currentStep],
                elementPosition = _getOffset(currentElement.element),
                widthHeightPadding = 10;

            if (currentElement.position == 'floating') {
                widthHeightPadding = 0;
            }

            //set new position to helper layer
            helperLayer.setAttribute('style', 'width: ' + (elementPosition.width  + widthHeightPadding)  + 'px; ' +
            'height:' + (elementPosition.height + widthHeightPadding)  + 'px; ' +
            'top:'    + (elementPosition.top    - 5)   + 'px;' +
            'left: '  + (elementPosition.left   - 5)   + 'px;');

        }
    }

    /**
     * Add disableinteraction layer and adjust the size and position of the layer
     *
     * @api private
     * @method _disableInteraction
     */
    function _disableInteraction () {
        var disableInteractionLayer = document.querySelector('.introjs-disableInteraction');
        if (disableInteractionLayer === null) {
            disableInteractionLayer = document.createElement('div');
            disableInteractionLayer.className = 'introjs-disableInteraction';
            this._targetElement.appendChild(disableInteractionLayer);
        }

        _setHelperLayerPosition.call(this, disableInteractionLayer);
    }

    /**
     * Show an element on the page
     *
     * @api private
     * @method _showElement
     * @param {Object} targetElement
     */
    function _showElement(targetElement) {

        if (typeof (this._introChangeCallback) !== 'undefined') {
            this._introChangeCallback.call(this, targetElement.element);
        }

        var self = this,
            oldHelperLayer = document.querySelector('.introjs-helperLayer'),
            oldReferenceLayer = document.querySelector('.introjs-tooltipReferenceLayer'),
            highlightClass = 'introjs-helperLayer',
            elementPosition = _getOffset(targetElement.element);

        //check for a current step highlight class
        if (typeof (targetElement.highlightClass) === 'string') {
            highlightClass += (' ' + targetElement.highlightClass);
        }
        //check for options highlight class
        if (typeof (this._options.highlightClass) === 'string') {
            highlightClass += (' ' + this._options.highlightClass);
        }

        if (oldHelperLayer != null) {
            var oldHelperNumberLayer = oldReferenceLayer.querySelector('.introjs-helperNumberLayer'),
                oldtooltipLayer      = oldReferenceLayer.querySelector('.introjs-tooltiptext'),
                oldArrowLayer        = oldReferenceLayer.querySelector('.introjs-arrow'),
                oldtooltipContainer  = oldReferenceLayer.querySelector('.introjs-tooltip'),
                skipTooltipButton    = oldReferenceLayer.querySelector('.introjs-skipbutton'),
                prevTooltipButton    = oldReferenceLayer.querySelector('.introjs-prevbutton'),
                nextTooltipButton    = oldReferenceLayer.querySelector('.introjs-nextbutton');

            //update or reset the helper highlight class
            oldHelperLayer.className = highlightClass;
            //hide the tooltip
            oldtooltipContainer.style.opacity = 0;
            oldtooltipContainer.style.display = "none";

            if (oldHelperNumberLayer != null) {
                var lastIntroItem = this._introItems[(targetElement.step - 2 >= 0 ? targetElement.step - 2 : 0)];

                if (lastIntroItem != null && (this._direction == 'forward' && lastIntroItem.position == 'floating') || (this._direction == 'backward' && targetElement.position == 'floating')) {
                    oldHelperNumberLayer.style.opacity = 0;
                }
            }

            //set new position to helper layer
            _setHelperLayerPosition.call(self, oldHelperLayer);
            _setHelperLayerPosition.call(self, oldReferenceLayer);

            //remove `introjs-fixParent` class from the elements
            var fixParents = document.querySelectorAll('.introjs-fixParent');
            if (fixParents && fixParents.length > 0) {
                for (var i = fixParents.length - 1; i >= 0; i--) {
                    fixParents[i].className = fixParents[i].className.replace(/introjs-fixParent/g, '').replace(/^\s+|\s+$/g, '');
                };
            }

            //remove old classes
            var oldShowElement = document.querySelector('.introjs-showElement');
            oldShowElement.className = oldShowElement.className.replace(/introjs-[a-zA-Z]+/g, '').replace(/^\s+|\s+$/g, '');

            //we should wait until the CSS3 transition is competed (it's 0.3 sec) to prevent incorrect `height` and `width` calculation
            if (self._lastShowElementTimer) {
                clearTimeout(self._lastShowElementTimer);
            }
            self._lastShowElementTimer = setTimeout(function() {
                //set current step to the label
                if (oldHelperNumberLayer != null) {
                    oldHelperNumberLayer.innerHTML = targetElement.step;
                }
                //set current tooltip text
                oldtooltipLayer.innerHTML = targetElement.intro;
                //set the tooltip position
                oldtooltipContainer.style.display = "block";
                _placeTooltip.call(self, targetElement.element, oldtooltipContainer, oldArrowLayer, oldHelperNumberLayer);

                //change active bullet
                oldReferenceLayer.querySelector('.introjs-bullets li > a.active').className = '';
                oldReferenceLayer.querySelector('.introjs-bullets li > a[data-stepnumber="' + targetElement.step + '"]').className = 'active';

                oldReferenceLayer.querySelector('.introjs-progress .introjs-progressbar').setAttribute('style', 'width:' + _getProgress.call(self) + '%;');

                //show the tooltip
                oldtooltipContainer.style.opacity = 1;
                if (oldHelperNumberLayer) oldHelperNumberLayer.style.opacity = 1;

                //reset button focus
                if (nextTooltipButton.tabIndex === -1) {
                    //tabindex of -1 means we are at the end of the tour - focus on skip / done
                    skipTooltipButton.focus();
                } else {
                    //still in the tour, focus on next
                    nextTooltipButton.focus();
                }
            }, 350);

        } else {
            var helperLayer       = document.createElement('div'),
                referenceLayer    = document.createElement('div'),
                arrowLayer        = document.createElement('div'),
                tooltipLayer      = document.createElement('div'),
                tooltipTextLayer  = document.createElement('div'),
                bulletsLayer      = document.createElement('div'),
                progressLayer     = document.createElement('div'),
                buttonsLayer      = document.createElement('div');

            helperLayer.className = highlightClass;
            referenceLayer.className = 'introjs-tooltipReferenceLayer';

            //set new position to helper layer
            _setHelperLayerPosition.call(self, helperLayer);
            _setHelperLayerPosition.call(self, referenceLayer);

            //add helper layer to target element
            this._targetElement.appendChild(helperLayer);
            this._targetElement.appendChild(referenceLayer);

            arrowLayer.className = 'introjs-arrow';

            tooltipTextLayer.className = 'introjs-tooltiptext';
            tooltipTextLayer.innerHTML = targetElement.intro;

            bulletsLayer.className = 'introjs-bullets';

            if (this._options.showBullets === false) {
                bulletsLayer.style.display = 'none';
            }

            var ulContainer = document.createElement('ul');

            for (var i = 0, stepsLength = this._introItems.length; i < stepsLength; i++) {
                var innerLi    = document.createElement('li');
                var anchorLink = document.createElement('a');

                anchorLink.onclick = function() {
                    self.goToStep(this.getAttribute('data-stepnumber'));
                };

                if (i === (targetElement.step-1)) anchorLink.className = 'active';

                anchorLink.href = 'javascript:void(0);';
                anchorLink.innerHTML = "&nbsp;";
                anchorLink.setAttribute('data-stepnumber', this._introItems[i].step);

                innerLi.appendChild(anchorLink);
                ulContainer.appendChild(innerLi);
            }

            bulletsLayer.appendChild(ulContainer);

            progressLayer.className = 'introjs-progress';

            if (this._options.showProgress === false) {
                progressLayer.style.display = 'none';
            }
            var progressBar = document.createElement('div');
            progressBar.className = 'introjs-progressbar';
            progressBar.setAttribute('style', 'width:' + _getProgress.call(this) + '%;');

            progressLayer.appendChild(progressBar);

            buttonsLayer.className = 'introjs-tooltipbuttons';
            if (this._options.showButtons === false) {
                buttonsLayer.style.display = 'none';
            }

            tooltipLayer.className = 'introjs-tooltip';
            tooltipLayer.appendChild(tooltipTextLayer);
            tooltipLayer.appendChild(bulletsLayer);
            tooltipLayer.appendChild(progressLayer);

            //add helper layer number
            if (this._options.showStepNumbers == true) {
                var helperNumberLayer = document.createElement('span');
                helperNumberLayer.className = 'introjs-helperNumberLayer';
                helperNumberLayer.innerHTML = targetElement.step;
                referenceLayer.appendChild(helperNumberLayer);
            }

            tooltipLayer.appendChild(arrowLayer);
            referenceLayer.appendChild(tooltipLayer);

            //next button
            var nextTooltipButton = document.createElement('a');

            nextTooltipButton.onclick = function() {
                if (self._introItems.length - 1 != self._currentStep) {
                    _nextStep.call(self);
                }
            };

            nextTooltipButton.href = 'javascript:void(0);';
            nextTooltipButton.innerHTML = this._options.nextLabel;

            //previous button
            var prevTooltipButton = document.createElement('a');

            prevTooltipButton.onclick = function() {
                if (self._currentStep != 0) {
                    _previousStep.call(self);
                }
            };

            prevTooltipButton.href = 'javascript:void(0);';
            prevTooltipButton.innerHTML = this._options.prevLabel;

            //skip button
            var skipTooltipButton = document.createElement('a');
            skipTooltipButton.className = 'introjs-button introjs-skipbutton';
            skipTooltipButton.href = 'javascript:void(0);';
            skipTooltipButton.innerHTML = this._options.skipLabel;

            skipTooltipButton.onclick = function() {
                if (self._introItems.length - 1 == self._currentStep && typeof (self._introCompleteCallback) === 'function') {
                    self._introCompleteCallback.call(self);
                }

                if (self._introItems.length - 1 != self._currentStep && typeof (self._introExitCallback) === 'function') {
                    self._introExitCallback.call(self);
                }

                _exitIntro.call(self, self._targetElement);
            };

            buttonsLayer.appendChild(skipTooltipButton);

            //in order to prevent displaying next/previous button always
            if (this._introItems.length > 1) {
                buttonsLayer.appendChild(prevTooltipButton);
                buttonsLayer.appendChild(nextTooltipButton);
            }

            tooltipLayer.appendChild(buttonsLayer);

            //set proper position
            _placeTooltip.call(self, targetElement.element, tooltipLayer, arrowLayer, helperNumberLayer);
        }

        //disable interaction
        if (this._options.disableInteraction === true) {
            _disableInteraction.call(self);
        }

        prevTooltipButton.removeAttribute('tabIndex');
        nextTooltipButton.removeAttribute('tabIndex');

        if (this._currentStep == 0 && this._introItems.length > 1) {
            prevTooltipButton.className = 'introjs-button introjs-prevbutton introjs-disabled';
            prevTooltipButton.tabIndex = '-1';
            nextTooltipButton.className = 'introjs-button introjs-nextbutton';
            skipTooltipButton.innerHTML = this._options.skipLabel;
        } else if (this._introItems.length - 1 == this._currentStep || this._introItems.length == 1) {
            skipTooltipButton.innerHTML = this._options.doneLabel;
            prevTooltipButton.className = 'introjs-button introjs-prevbutton';
            nextTooltipButton.className = 'introjs-button introjs-nextbutton introjs-disabled';
            nextTooltipButton.tabIndex = '-1';
        } else {
            prevTooltipButton.className = 'introjs-button introjs-prevbutton';
            nextTooltipButton.className = 'introjs-button introjs-nextbutton';
            skipTooltipButton.innerHTML = this._options.skipLabel;
        }

        //Set focus on "next" button, so that hitting Enter always moves you onto the next step
        nextTooltipButton.focus();

        //add target element position style
        targetElement.element.className += ' introjs-showElement';

        var currentElementPosition = _getPropValue(targetElement.element, 'position');
        if (currentElementPosition !== 'absolute' &&
            currentElementPosition !== 'relative') {
            //change to new intro item
            targetElement.element.className += ' introjs-relativePosition';
        }

        var parentElm = targetElement.element.parentNode;
        while (parentElm != null) {
            if (parentElm.tagName.toLowerCase() === 'body') break;

            //fix The Stacking Contenxt problem.
            //More detail: https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Understanding_z_index/The_stacking_context
            var zIndex = _getPropValue(parentElm, 'z-index');
            var opacity = parseFloat(_getPropValue(parentElm, 'opacity'));
            var transform = _getPropValue(parentElm, 'transform') || _getPropValue(parentElm, '-webkit-transform') || _getPropValue(parentElm, '-moz-transform') || _getPropValue(parentElm, '-ms-transform') || _getPropValue(parentElm, '-o-transform');
            if (/[0-9]+/.test(zIndex) || opacity < 1 || (transform !== 'none' && transform !== undefined)) {
                parentElm.className += ' introjs-fixParent';
            }

            parentElm = parentElm.parentNode;
        }

        if (!_elementInViewport(targetElement.element) && this._options.scrollToElement === true) {
            var rect = targetElement.element.getBoundingClientRect(),
                winHeight = _getWinSize().height,
                top = rect.bottom - (rect.bottom - rect.top),
                bottom = rect.bottom - winHeight;

            //Scroll up
            if (top < 0 || targetElement.element.clientHeight > winHeight) {
                window.scrollBy(0, top - 30); // 30px padding from edge to look nice

                //Scroll down
            } else {
                window.scrollBy(0, bottom + 100); // 70px + 30px padding from edge to look nice
            }
        }

        if (typeof (this._introAfterChangeCallback) !== 'undefined') {
            this._introAfterChangeCallback.call(this, targetElement.element);
        }
    }

    /**
     * Get an element CSS property on the page
     * Thanks to JavaScript Kit: http://www.javascriptkit.com/dhtmltutors/dhtmlcascade4.shtml
     *
     * @api private
     * @method _getPropValue
     * @param {Object} element
     * @param {String} propName
     * @returns Element's property value
     */
    function _getPropValue (element, propName) {
        var propValue = '';
        if (element.currentStyle) { //IE
            propValue = element.currentStyle[propName];
        } else if (document.defaultView && document.defaultView.getComputedStyle) { //Others
            propValue = document.defaultView.getComputedStyle(element, null).getPropertyValue(propName);
        }

        //Prevent exception in IE
        if (propValue && propValue.toLowerCase) {
            return propValue.toLowerCase();
        } else {
            return propValue;
        }
    }

    /**
     * Provides a cross-browser way to get the screen dimensions
     * via: http://stackoverflow.com/questions/5864467/internet-explorer-innerheight
     *
     * @api private
     * @method _getWinSize
     * @returns {Object} width and height attributes
     */
    function _getWinSize() {
        if (window.innerWidth != undefined) {
            return { width: window.innerWidth, height: window.innerHeight };
        } else {
            var D = document.documentElement;
            return { width: D.clientWidth, height: D.clientHeight };
        }
    }

    /**
     * Add overlay layer to the page
     * http://stackoverflow.com/questions/123999/how-to-tell-if-a-dom-element-is-visible-in-the-current-viewport
     *
     * @api private
     * @method _elementInViewport
     * @param {Object} el
     */
    function _elementInViewport(el) {
        var rect = el.getBoundingClientRect();

        return (
        rect.top >= 0 &&
        rect.left >= 0 &&
        (rect.bottom+80) <= window.innerHeight && // add 80 to get the text right
        rect.right <= window.innerWidth
        );
    }

    /**
     * Add overlay layer to the page
     *
     * @api private
     * @method _addOverlayLayer
     * @param {Object} targetElm
     */
    function _addOverlayLayer(targetElm) {
        var overlayLayer = document.createElement('div'),
            styleText = '',
            self = this;

        //set css class name
        overlayLayer.className = 'introjs-overlay';

        //check if the target element is body, we should calculate the size of overlay layer in a better way
        if (targetElm.tagName.toLowerCase() === 'body') {
            styleText += 'top: 0;bottom: 0; left: 0;right: 0;position: fixed;';
            overlayLayer.setAttribute('style', styleText);
        } else {
            //set overlay layer position
            var elementPosition = _getOffset(targetElm);
            if (elementPosition) {
                styleText += 'width: ' + elementPosition.width + 'px; height:' + elementPosition.height + 'px; top:' + elementPosition.top + 'px;left: ' + elementPosition.left + 'px;';
                overlayLayer.setAttribute('style', styleText);
            }
        }

        targetElm.appendChild(overlayLayer);

        overlayLayer.onclick = function() {
            if (self._options.exitOnOverlayClick == true) {

                //check if any callback is defined
                if (self._introExitCallback != undefined) {
                    self._introExitCallback.call(self);
                }
                _exitIntro.call(self, targetElm);
            }
        };

        setTimeout(function() {
            styleText += 'opacity: ' + self._options.overlayOpacity.toString() + ';';
            overlayLayer.setAttribute('style', styleText);
        }, 10);

        return true;
    }

    /**
     * Get an element position on the page
     * Thanks to `meouw`: http://stackoverflow.com/a/442474/375966
     *
     * @api private
     * @method _getOffset
     * @param {Object} element
     * @returns Element's position info
     */
    function _getOffset(element) {
        var elementPosition = {};

        //set width
        elementPosition.width = element.offsetWidth;

        //set height
        elementPosition.height = element.offsetHeight;

        //calculate element top and left
        var _x = 0;
        var _y = 0;
        while (element && !isNaN(element.offsetLeft) && !isNaN(element.offsetTop)) {
            _x += element.offsetLeft;
            _y += element.offsetTop;
            element = element.offsetParent;
        }
        //set top
        elementPosition.top = _y;
        //set left
        elementPosition.left = _x;

        return elementPosition;
    }

    /**
     * Gets the current progress percentage
     *
     * @api private
     * @method _getProgress
     * @returns current progress percentage
     */
    function _getProgress() {
        // Steps are 0 indexed
        var currentStep = parseInt((this._currentStep + 1), 10);
        return ((currentStep / this._introItems.length) * 100);
    }

    /**
     * Overwrites obj1's values with obj2's and adds obj2's if non existent in obj1
     * via: http://stackoverflow.com/questions/171251/how-can-i-merge-properties-of-two-javascript-objects-dynamically
     *
     * @param obj1
     * @param obj2
     * @returns obj3 a new object based on obj1 and obj2
     */
    function _mergeOptions(obj1,obj2) {
        var obj3 = {};
        for (var attrname in obj1) { obj3[attrname] = obj1[attrname]; }
        for (var attrname in obj2) { obj3[attrname] = obj2[attrname]; }
        return obj3;
    }

    var introJs = function (targetElm) {
        if (typeof (targetElm) === 'object') {
            //Ok, create a new instance
            return new IntroJs(targetElm);

        } else if (typeof (targetElm) === 'string') {
            //select the target element with query selector
            var targetElement = document.querySelector(targetElm);

            if (targetElement) {
                return new IntroJs(targetElement);
            } else {
                throw new Error('There is no element with given selector.');
            }
        } else {
            return new IntroJs(document.body);
        }
    };

    /**
     * Current IntroJs version
     *
     * @property version
     * @type String
     */
    introJs.version = VERSION;

    //Prototype
    introJs.fn = IntroJs.prototype = {
        clone: function () {
            return new IntroJs(this);
        },
        setOption: function(option, value) {
            this._options[option] = value;
            return this;
        },
        setOptions: function(options) {
            this._options = _mergeOptions(this._options, options);
            return this;
        },
        start: function () {
            _introForElement.call(this, this._targetElement);
            return this;
        },
        goToStep: function(step) {
            _goToStep.call(this, step);
            return this;
        },
        nextStep: function() {
            _nextStep.call(this);
            return this;
        },
        previousStep: function() {
            _previousStep.call(this);
            return this;
        },
        exit: function() {
            _exitIntro.call(this, this._targetElement);
            return this;
        },
        refresh: function() {
            _setHelperLayerPosition.call(this, document.querySelector('.introjs-helperLayer'));
            _setHelperLayerPosition.call(this, document.querySelector('.introjs-tooltipReferenceLayer'));
            return this;
        },
        onbeforechange: function(providedCallback) {
            if (typeof (providedCallback) === 'function') {
                this._introBeforeChangeCallback = providedCallback;
            } else {
                throw new Error('Provided callback for onbeforechange was not a function');
            }
            return this;
        },
        onchange: function(providedCallback) {
            if (typeof (providedCallback) === 'function') {
                this._introChangeCallback = providedCallback;
            } else {
                throw new Error('Provided callback for onchange was not a function.');
            }
            return this;
        },
        onafterchange: function(providedCallback) {
            if (typeof (providedCallback) === 'function') {
                this._introAfterChangeCallback = providedCallback;
            } else {
                throw new Error('Provided callback for onafterchange was not a function');
            }
            return this;
        },
        oncomplete: function(providedCallback) {
            if (typeof (providedCallback) === 'function') {
                this._introCompleteCallback = providedCallback;
            } else {
                throw new Error('Provided callback for oncomplete was not a function.');
            }
            return this;
        },
        onexit: function(providedCallback) {
            if (typeof (providedCallback) === 'function') {
                this._introExitCallback = providedCallback;
            } else {
                throw new Error('Provided callback for onexit was not a function.');
            }
            return this;
        }
    };

    exports.introJs = introJs;
    return introJs;
}));
